1. Field of the Invention
The present invention relates to a method of collecting saliva from the oral cavity for detecting a test substance, a saliva-collecting solution for obtaining saliva, containers for biological fluids comprising a base part and a cover part, each with an external face and an internal face, the cover part having a cut-out in the form of a recess in which a transfer mechanism is disposed and incorporates a mechanism for penetrating a collection vessel provided on the external face of the cover part and a projection with two ends provided on the internal face of the cover part, a sealable collection vessel for accommodating biological fluids such as blood, for example, with an internal face directed towards a biological sample, a saliva simulation solution for imitating the composition of physiological saliva, a calibrator solution for quantifying the volume of saliva, a test kit for obtaining saliva and applications thereof.
2. Prior Art
Blood is predominantly used in both human and veterinary medicine as a means of analysing parameters of a clinically chemical nature. However, there are also other bodily fluids which provide information about the state of a patient. They differ in the way they are accessed.
The disadvantages of blood as an analysis material are its complex matrix, a limited availability, the need for qualified personnel to take samples and the time involved in this process, as well as the discomfort of the patient, accompanied by pain and stress.
Saliva is produced exclusively by three large and numerous smaller saliva glands and is predominantly generated in the oral cavity. When taking samples, it is necessary to distinguish between glandular saliva which is produced by the glands only and is taken from the relevant discharge point and mixed saliva originating in the oral cavity. Glandular saliva is primarily needed for scientific tests relating to the physiology and pathology of a specific type of gland and transport phenomena, whereas mixed saliva can predominantly be used for routine diagnostic tests which enable conclusions to be drawn about blood elements.
Saliva is a sample material that is easy to collect without causing stress and can be used for a whole series of analytical purposes. Amongst other things, saliva tests provide valuable information for diagnostic purposes and for controlling the treatment of a number of diseases. It enables proteins, hormones, metabolic metabolites, electrolytes and various pharmaceutical substances to be tested.
The use of saliva offers a number of advantages for clinical chemical diagnosis. For the patient, there are a number of different advantages to using saliva instead of blood.
The lesser discomfort to which the patient is subjected means that there is virtually no stress involved in obtaining a sample. Consequently, saliva diagnosis is of particular interest for all studies in which the hypothalamus-hypophysis-suprarenal gland axis plays a role. It is a generally known fact that repeated puncturing of the veins can mask the response of many dynamic functional tests.
Saliva diagnosis is also attractive for all tests which require frequent sampling, such as detecting biorhythms, monitoring ovulation and therapeutic treatment, for example.
In addition, there is less risk to the patient of artificial anaemia, infections and thromboses than is the case with blood samples.
Another advantage of using saliva is the lower cost of obtaining the sample because staffing costs are relatively low overall since there is no need for sampling to be done by trained doctors or nursing staff. Samples of saliva can even be taken by the patient himself and then sent to an appropriate specialist laboratory.
The use of saliva also offers a number of advantages in terms of diagnosis, such as the reflection of non-protein-bonded plasma fractions, the reflection of cellular concentration ratios, no volume pressure effect due to lipids and, in the case of some medicaments, a better correlation between the saliva concentration and the pharmacological effects.
Although saliva is produced constantly in the waking state, a total of approximately 1000 ml in 24 hours, and can be readily taken from the oral cavity, problems can also arise when collecting saliva samples, especially in the case of older patients.
Various methods and devices for taking samples of saliva are already known from the prior art.
In the simplest case, the flow of saliva is stimulated by chewing movements. Under certain conditions, however, this stimulation is not enough, for example in the case of dialysis patients and older patients, particularly in the morning after waking.
Another method is saliva collection using a Salivette®, whereby saliva is obtained by chewing on a roll of cotton wool. To obtain the saliva, the fully soaked cotton wool roll is inserted in the Salivette suspension vessel and centrifuged. The transparent saliva present is available for analysis. If solid substrates such as cotton wool are used to obtain the saliva sample, for example, it is necessary to check whether substances from whatever material was used has been adsorbed. This is of particular importance when testing for medicaments.
The flow of saliva can also be stimulated by mechanical stimulation, such as chewing movements. To this end, a piece of chewing gum or paraffin wax of a standardised size is administered and the patient is required to chew it for a certain time at a speed of 70 chewing movements/min, for example, in which case the rate of chewing movements can be monitored by means of a metronome and the saliva that has been generated in the oral cavity can be collected after 1 to 2 min.
The spitting method can also be used as a means of collecting a sample of mixed saliva. With this method, the saliva in the oral cavity is simply spat out. This procedure has to be repeated at specific time intervals.
An alternative method of obtaining saliva samples is a method whereby saliva is sucked out of the oral cavity by means of an aspirator, in which case the saliva that has collected in the oral cavity is sucked out for a predetermined period of time.
Saliva that has collected in the oral cavity can also be simply dripped out into a sample vessel.
However, the disadvantage which all of the above methods have in common is the fact that only a very small quantity of saliva can be collected from patients or, in the case of persons who have a low saliva flow, the taking of samples is not reproducible, the volume is barely quantifiable and thus gives rise to problems when it comes to using it for diagnostic purposes.